A typical data storage system includes one or more data storage disks coaxially mounted on a hub of a spindle motor. The spindle motor rotates the disks at speeds typically on the order of several thousand revolutions-per-minute. Digital information, representing various types of data, is typically written to and read from the data storage disks by one or more transducers, or read/write heads, which are mounted to an actuator and passed over the surface of the rapidly rotating disks.
The actuator typically includes a plurality of outwardly extending arms with one or more transducers being mounted resiliently or rigidly on the extreme end of the arms. The actuator arms are interleaved into and out of the stack of rotating disks, typically by means of a coil assembly mounted to the actuator. The coil assembly generally interacts with a permanent magnet structure, and the application of current to the coil in one polarity causes the actuator arms and transducers to shift in one direction, while current of the opposite polarity shifts the actuator arms and transducers in an opposite direction.
In a typical digital data storage system, digital data is stored in the form of magnetic transitions on a series of concentric, closely spaced tracks comprising the surface of the magnetizable rigid data storage disks. The tracks are generally divided into a plurality of sectors, with each sector comprising a number of information fields. One of the information fields is typically designated for storing data, while other fields contain sector identification and synchronization information, for example. Data is transferred to, and retrieved from, specified track and sector locations by the transducers being shifted from track to track, typically under the control of a controller. The transducer assembly typically includes a read element and a write element. Other transducer assembly configurations incorporate a single transducer element used to write data to the disks and read data from the disks.
Writing data to a data storage disk generally involves passing a current through the write element of the transducer assembly to produce magnetic lines of flux which magnetize a specific location of the disk surface. Reading data from a specified disk location is typically accomplished by a read element of the transducer assembly sensing the magnetic field or flux lines emanating from the magnetized locations of the disk. As the read element passes over the rotating disk surface, the interaction between the read element and the magnetized locations on the disk surface results in the production of electrical pulses in the read element. The electrical pulses correspond to transitions in the magnetic field.
A trend has developed in the data storage system manufacturing community to miniaturize the chassis or housing of a data storage system to a size suitable for incorporation into miniature personal computers, such as lap-top and pocket-sized computers, for example. Various industry standards have emerged that specify the external housing dimensions of small and very small form factor data storage systems. One such recognized family of industry standards is the PCMCIA (Personal Computer Memory Card Industry Association) family of standards, which specifies both the dimensions for the data storage system housing and the protocol for communicating control and data signals between the data storage system and a host computer system coupled thereto. Recently, four families or types of PCMCIA device specifications have emerged. By way of example, a Type-I PCMCIA data storage system must be fully contained within a housing having a maximum height dimension of 3.3 millimeters (mm). By way of further example, a Type-II PCMCIA device housing must not exceed a maximum height of 5.0 mm in accordance with the PCMCIA specification. A maximum height of 10.5 mm is specified for the housing of Type-III PCMCIA devices, and Type-IV devices are characterized as having a maximum housing height dimension in excess of 10.5 mm.
It is anticipated that the industry trend of continued miniaturization of data storage systems will eventually result in the production of systems complying with the Type-II PCMCIA specification. Such Type-II PCMCIA data storage systems will likely have external housing dimensions of approximately 54 mm.times.86 mm.times.5 mm, and include a data storage disk having a diameter of approximately 45 mm and a width dimension similar to that of a standard credit card. The trend toward reducing data storage system housing dimensions imposes a number of design constraints that often necessitate employment of new and previously untried methods for mounting system components within the relatively compact housing configuration of relatively small form factor systems. Such data storage systems must also generally be designed for manufacture in a high-volume production environment. Minimizing the number of system components and the complexity of assembling these components is generally of considerable concern, as inefficient assembly practices negatively impact the cost and rate of manufacturing such systems.
There exists in the data storage system manufacturing industry a keenly felt need to provide an apparatus that facilitates efficient top-down assembly of system components within the data storage system housing, and, in particular, the rotatable actuator. Prior art actuator mounting schemes typically employ a plurality of mounting screws to secure the actuator shaft to an internal sub-structure provided within the housing. One conventional actuator mounting scheme, for example, employs a bottom mounting screw for securing a bottom portion of the actuator shaft to the substructure and a top mounting screw to secure the top portion of the actuator shaft to the sub-structure.
Such prior art actuator mounting schemes are generally not suitable for use in data storage systems designed for manufacture in an efficient top-down assembly environment. Installation of the bottom mounting screw, for example, generally requires that the partially assembled data storage system be turned upside-down, thereby dislodging any unsecured or partially installed system component or requiring various retention arrangements or fasteners to secure movably mounted and unsecured components. The additional supporting sub-structures and retention arrangement associated with conventional actuator mounting schemes generally add to the cost and complexity of the data storage system and procedures for manufacturing such systems. Moreover, these and other prior art actuator mounting schemes are generally not suitable for employment within the compact packaging configurations of small and very small form factor data storage system housings.